Alternatives & variations Download PDF datasheet

25D4

Indirectly heated half-wave rectifier for television horizontal-deflection damping, with approximately 4.4 kV inverse-voltage and 900 mA peak-current capability.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: 8
Nominal heater: 25 V / 300 mA

Description

The 25D4 is an indirectly heated half-wave rectifier designed for damping-diode service in horizontal-deflection circuits of series-heater television receivers, with controlled heater warm-up characteristics.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: 8
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Rectifier

X-ray radiationInterelectrode capacitances

Max plate dissipation: 5.5 W
Rectifier peak inverse voltage: 4400 V
Rectifier nominal output current: 155 mA
Rectifier peak forward current: 900 mA
Rectifier forward voltage drop: 22 V
Rectifier max heater-cathode voltage: 4400 V
Rectifier warm-up time: 11 s

Damper diode; design-center DC plate current also published as 145 mA.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

Heater voltage
25 V
Nominal
Heater current
300 mA
Nominal
Maximum DC plate current
155 mA
DamperService
Maximum peak plate current
900 mA
DamperService
Heater-cathode voltage, heater negative, DC and peak
4400 V
DamperService
Heater-cathode voltage, heater positive, DC and peak
300 V
DamperService

Characteristic

Tube voltage drop at 250 mA
22 V
DamperService
Heater warm-up time
11 s
ControlledWarmup

Capacitance

Heater to cathode
3 pF
Approximate
Plate to cathode and heater
6 pF
Approximate
Cathode to plate and heater
8 pF
Approximate

Data set 02

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

Maximum peak inverse voltage
4400 V
HorizontalDeflection
Maximum DC plate current
155 mA
WholeTube
Design-center DC plate current
145 mA
WholeTube
Maximum peak plate current
900 mA
WholeTube

Characteristic

Heater-to-cathode capacitance
3 pF
WholeTube
Plate-to-cathode-and-heater capacitance
6 pF
WholeTube
Cathode-to-plate-and-heater capacitance
8 pF
WholeTube